of the Endosperm during Germination. 455 



EXPLANATION OF PLATE V. 



Figures 1 — 10, Tamus communis. 



Fig, 1. Seed of Tamus at the commencement of germination, the 

 radicle has just pushed open the lid-like portion of the 

 testa around the micropyle. m. micropyle ; r. radicle. 



Fig. 2. A slightly older stage than Fig. 1. The micropyle lid, m., 



seen from above. 



i 



Fig. 3. The embryo and seed in section as in fig. 2 shewing the testa 

 composed of thick-walled cells ; the ' lid ' surmounted by 

 the micropyle and the radially arranged endosperm cells. 

 In the embryo the cotyledon (c.) embedded in the endo- 

 sperm (e.), the first leaf (I.) covered by the cotyledonary 

 sheath (s.) and the extruded radicle (r.) are seen. t. testa. 

 The line (c.) does not reach the cotyledon. 



Fig. 4. A more advanced stage of germination. The first leaf (I.) of 

 the plumule has pushed aside the two lobes of the coty- 

 ledonary sheath (s.) and commenced to grow upwards. 



Fig. 5. The young seedling shewing the formation of the tuber (T.) 

 at the base of the first leaf ; the first leaf possesses a 

 sharply incurved tip. 



Fig. 6. A young epicotyledonary tuber full of starch seen in section, 

 s. starch, e. endosperm, T. the base of the cotyledon. 



Fig. 7. An adult seedling in its first year, shewing the seed, to which 

 the large tuber (T.), with its adventitious roots, still 

 remains attached, the long petiole and expanded lamina 

 of the first leaf. The dotted line marks the level of the 

 soil. 



Fig. 8. A section of the endosperm near the centre of a germinating 

 seed; the cells are here rounded and possess thick walls, 

 which are well provided with connecting threads as at x. 

 Various stages of the action of the ferment on the wall 

 can be seen. As soon as an entrance into the wall has 

 been effected along one or more of the threads the ferment 

 proceeds to dissolve the wall, especially in the region of 



